This invention relates generally to motor vehicle frames and more particulary to a pressured structural member of a vehicle frame.
The frame is a large part of the total weight of a motor vehicle and is also a large part of the protection provided for vehicle occupants. Engineers are constantly looking for ways to reduge the weight of the vehicle frame, to improve fuel economy and to reduce cost, but without sacrificing the rigidity and buckle strength of the structural members that make up the frame.
In accordance with the present invention, one or more of the structural members of the vehicle frame are hollow to reduce its weight. Filler material occupies a major portion of the chamber. The filler material is less dense than the structural material and the cost is lower. Spring means in the chamber imposes a constant force on the filler material to press the filler material outwardly against the walls of the structural member. The internal pressure on the walls of the structural member increases its strength and resistance to buckling.
Further in accordance with the invention, a compression coil spring is provided at one end of the chamber. Although not a requirement, a pressure plate is placed between the spring and the filler material. A second spring may be provided at the opposite end of the chamber to compress the filler material at both ends. A center spring may be added, if desired.
The filler material is preferably formed of relatively small incompressible particles which may be pebbles or cut-up parts of rubber tires or any inexpensive solid material that may be selected to fill the chamber. Although not a requirement, the filler material may be contained within a bag to prevent shear forces between the filler material and the structural member. Highly viscous fluids such as gels and pastes can be used as filler material. The filler material should be incompressible, non-leaking, inexpensive and low density.
One object of this invention is to provide a pressurized structural member for the frame of a motor vehicle which is of reduced weight and cost but which also is highly resistant to buckling.
Another object is to provide a pressurized structural member which does not have the disadvantage of leakage associated with stored-gas-pressurized structures.
Another object of the invention is to provide a pressurized structural member for the vehicle frame which is composed of a relatively few simple parts, is rugged and durable in use, and is highly effective in the performance of its intended function.
These and other objects, features and advantages of the invention will become more apparent as the following description proceeds, especially when considered with the accompanying drawings.